Handle errors in DoesTableExist() gracefully instead of crashing.

BUG=30403
TEST=None

Review URL: http://codereview.chromium.org/500040

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@34760 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 25 insertions, 6 deletions

diff --git a/chrome/browser/sync/syncable/directory_backing_store.cc b/chrome/browser/sync/syncable/directory_backing_store.cc
index 7093043..ac85e56 100755
--- a/chrome/browser/sync/syncable/directory_backing_store.cc
+++ b/chrome/browser/sync/syncable/directory_backing_store.cc
@@ -306,7 +306,8 @@ DirOpenResult DirectoryBackingStore::InitializeTables() {
   }
   int version_on_disk = 0;
 
-  if (DoesTableExist(load_dbhandle_, "share_version")) {
+  bool exists = false;
+  if (DoesTableExist(load_dbhandle_, "share_version", &exists) && exists) {
     ScopedStatement version_query(
         PrepareQuery(load_dbhandle_, "SELECT data from share_version"));
     int query_result = sqlite3_step(version_query.get());
@@ -331,7 +332,10 @@ DirOpenResult DirectoryBackingStore::InitializeTables() {
     {
       ScopedStatement statement(PrepareQuery(load_dbhandle_,
           "SELECT db_create_version, db_create_time FROM share_info"));
-      CHECK(SQLITE_ROW == sqlite3_step(statement.get()));
+      if (SQLITE_ROW != sqlite3_step(statement.get())) {
+        ExecOrDie(load_dbhandle_, "ROLLBACK TRANSACTION");
+        return FAILED_DISK_FULL;
+      }
       string db_create_version;
       int db_create_time;
       GetColumn(statement.get(), 0, &db_create_version);
diff --git a/chrome/browser/sync/util/query_helpers.cc b/chrome/browser/sync/util/query_helpers.cc
index 46e8ee0..21d7e8e 100644
--- a/chrome/browser/sync/util/query_helpers.cc
+++ b/chrome/browser/sync/util/query_helpers.cc
@@ -26,6 +26,7 @@ sqlite3_stmt* PrepareQuery(sqlite3* dbhandle, const char* query) {
                                    CountBytes(query), &statement,
                                    &query_tail)) {
     LOG(ERROR) << query << "\n" << sqlite3_errmsg(dbhandle);
+    return NULL;
   }
   return statement;
 }
@@ -201,17 +202,25 @@ void GetColumn(sqlite3_stmt* statement, int index, std::vector<uint8>* value) {
   }
 }
 
-bool DoesTableExist(sqlite3* dbhandle, const string& table_name) {
+bool DoesTableExist(sqlite3* dbhandle, const string& table_name,
+                    bool* exists) {
+  CHECK(exists);
   ScopedStatement count_query
     (PrepareQuery(dbhandle,
                   "SELECT count(*) from sqlite_master where name = ?",
                   table_name));
 
+  if (!count_query.get())
+    return false;
+
   int query_result = sqlite3_step(count_query.get());
-  CHECK(SQLITE_ROW == query_result);
+  if (SQLITE_ROW != query_result)
+    return false;
+
   int count = sqlite3_column_int(count_query.get(), 0);
 
-  return 1 == count;
+  *exists = (1 == count);
+  return true;
 }
 
 void ScopedStatement::reset(sqlite3_stmt* statement) {
diff --git a/chrome/browser/sync/util/query_helpers.h b/chrome/browser/sync/util/query_helpers.h
index c44e635..3aedfe2 100644
--- a/chrome/browser/sync/util/query_helpers.h
+++ b/chrome/browser/sync/util/query_helpers.h
@@ -43,7 +43,13 @@ void GetColumn(sqlite3_stmt*, int index, double* value);
 void GetColumn(sqlite3_stmt*, int index, bool* value);
 void GetColumn(sqlite3_stmt*, int index, std::vector<uint8>* value);
 
-bool DoesTableExist(sqlite3* dbhandle, const std::string& tablename);
+// Checks if tablename exists in the database referenced by dbhandle.
+// If the function succeeds, *exists is set to true if the table exists, and
+// false if it doesn't.
+//
+// Returns true on success, or false on error.
+bool DoesTableExist(sqlite3* dbhandle, const std::string& tablename,
+                    bool* exists);
 
 // Prepares a query with a WHERE clause that filters the values by the items
 // passed inside of the Vector.